Keywords: aluminium, stress reduction, lifting brackets, finite elements, structural aluminium.

Prefabricated structural aluminium and aluminium alloy components have many competitive advantages, including light weight, high corrosion resistance and quick on site assembly. To assist moving the components around the fabrication shop and lifting the component into its final on site position fabricators weld aluminium lifting brackets onto low stress areas of the component.

In order to increase the efficiency of fabrication, reduce welding and reduce costs a fabricator wished to determine if changing from a fillet welded L shaped lifting bracket, welded on four sides to the component to a fillet welded T shaped lifting bracket welded to the component only on two opposite parallel sides would achieve the required efficiencies.

To determine if these efficiencies were achievable, this research used the finite element method to determined the maximum principal stresses in the existing L shaped lifting bracket, the proposed T shaped lifting bracket, the component and the fillet welds when the component was lifted.

A single 1000 N load was applied at the centre of the top surface of the lifting bracket and the following five load cases considered: a) load in the positive x direction, b) load in the negative x direction, c) load in the positive y direction, d) load in the positive z direction and e) load in the negative z direction. Four models were considered: Model A represented the L shaped lifting bracket, welded on the four vertical sides to the structural component. Model B was welded on all four vertical sides of the T shaped lifting bracket to the structural component. Model C was welded only on the two vertical sides of the T shaped lifting bracket parallel to the x axis to the structural component. Model D was welded only on the two vertical sides of the lifting bracket parallel to the y axis to the structural component. The principal stresses for Model A, the existing L shaped lifting bracket were taken as the values that Models B, C and D were compared with.

The results showed that only Models B and C always had maximum principal stresses that were lower then Model A. Thus Models B and C were recommended for use.

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